Separation of powers

Separation of powers is
a doctrine that is often believed to rest at the
foundation of the U.S. Constitution.
It holds that
liberty is best preserved if the three functions of
government—legislation, law enforcement, and
adjudication—are in different hands. The modern
idea of separation of powers is to be found in one
of the most important eighteenth-century works on
political science, the Baron de Montesquieu's The
Spirit of the Laws (1748), which states that "There
can be no liberty where the legislative and
executive powers are united in the same person, or
body of magistrates … [or] if the power of judging
be not separated from the legislative and executive
powers." In Federalist No. 47 (1788) James
Madison , commenting on Montesquieu's views and
seeking to reconcile them with the Constitution's
provisions, states that "The accumulation of all
powers, legislative, executive, and judiciary, in the
same hands, whether of one, a few, or many, and
whether hereditary, selfappointed [sic], or elective,
may justly be pronounced the very definition of
tyranny."
In truth, however, the Constitution does not strictly
adhere to the separation of powers, as the three
branches of the government—Congress, the
president, and the courts—have some overlap in
their constitutionally assigned functions. Thus,
although Congress is charged with legislation, a bill
does not become law until the president affixes his
signature, and the president may veto the
legislation, which can be overridden only by a two-
thirds vote of the House and Senate. Similarly, the
courts came to be recognized to have the power of
judicial review, pursuant to which they may declare
laws or executive acts to exceed the authorization
of the Constitution, and thus to be null and void.
Congress is given the power to impeach and try
executive and judicial branch officials for
misconduct; if found guilty, they are removed from
office. Presidential appointments to the judiciary or
to the cabinet require the approval of a majority
vote in the Senate; treaties negotiated by the
president require a two-thirds Senate majority.
These and other provisions are the famed "checks
and balances" within the Constitution, which are
believed to prevent the exercise of arbitrary power
by each of the branches.